Montana’s Dangerous Plant Hiding in Plain Sight

Montana’s breathtaking landscapes are home to a diverse range of plant life, but not all of it is harmless.

One of the most dangerous plants in the state is poison hemlock, and experts are urging residents to be on high alert, especially during the spring and summer months when the plant is in full growth.

What Is Poison Hemlock?

Poison hemlock (Conium maculatum) is a toxic biennial plant that grows along roadsides, trails, riverbanks, and even in residential areas. While it may look harmless, resembling wild carrot or Queen Anne’s lace, it’s anything but. Every part of the plant is highly poisonous: leaves, stems, seeds, and roots.

It’s not native to Montana. Poison hemlock is an invasive species brought to North America from Europe and North Africa, and it spreads aggressively, often crowding out native vegetation.

Why It's a Threat

What makes poison hemlock especially dangerous is how easy it is to come into contact with without realizing it. People who spend time outdoors, from gardeners, hikers, campers, or even children playing near wild vegetation, could unknowingly brush up against or handle the plant.

Ingestion, even in small amounts, can be fatal to humans and animals. Symptoms of poisoning include:

• Nausea and vomiting
• Tremors
• Respiratory distress
• Muscle paralysis
• Death from respiratory failure if untreated

Simply touching the plant can also cause skin irritation in some people, especially if the plant oils are absorbed through cuts or abrasions.

Spotting the Plant

Poison hemlock can grow between 6 to 10 feet tall. It has:

• Smooth, hollow stems with distinctive purple or reddish blotches
• Finely divided, fern-like leaves
• Small white flowers that grow in umbrella-shaped clusters
• A musty or “mouse-like” odor when crushed

It typically blooms between May and July, making this the prime time to watch for it.

Protecting Yourself and Others

Don’t touch or mess with any plants you’re not familiar with, especially ones that look like poison hemlock. It’s incredibly toxic, and even a little contact can cause problems. Talk to your kids about not picking wild plants, too, it’s better to be safe than sorry. If you’ve got pets or livestock, do your best to keep them away from areas where this plant might be growing.

If you need to get rid of poison hemlock on your property, suit up with gloves, long sleeves, and eye protection. Whatever you do, don’t burn it because the smoke can be dangerous to breathe in. If you spot poison hemlock anywhere, report it to your local extension office or the Montana Department of Agriculture so they can help handle it safely.

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Poison hemlock is a silent danger that’s easy to overlook, but knowing what to look for and how to protect yourself can make all the difference. When in doubt, admire plants from a distance and leave the identification to the experts.